The use of lightweight materials in the manufacture of vehicles, especially in the manufacture of spare parts and performance parts, is known from the state of the art. The use of light metals, such as aluminum and magnesium, for body parts and small parts has become generally accepted not only in racing or for small series, but also meanwhile in products for the mass public. In addition, because of their excellent ratio of weight to mechanical properties, fiber composites have lately been gaining increasing significance.
So that a component made of fiber-reinforced plastic can optimally absorb multiple stresses acting on it, it should also contain reinforcing fibers with multiple orientations, since they can absorb these forces, especially lengthwise. In addition, components made of fiber-reinforced plastic, which consist of continuous fiber layers, which ideally pass through the entire component, have proven to be successful.
In components which have complicated shapes and are highly stressed, such as, e.g., wheels, these requirements on the inner structure of fiber-reinforced components were usually not met up to now. This is the result of the fact that no process for the manufacture of a wheel, which can deposit continuous fibers corresponding to the geometry of a wheel, is known from the state of the art.
Therefore, in the state of the art, particularly processes for the manufacture of wheels are found in injection molding, wherein only very short reinforcing fibers are used in favor of the formability of the components. Another possibility is for the wheels to have a multipart design, whereby the simple geometry of the individual parts permits the construction thereof from long-fiber-reinforced plastics.
A vehicle wheel made of fiber-reinforced plastic as well as a process for the manufacture thereof is described in U.S. Pat. No. 3,917,352 A. In this case, the wheel has a one-part design and comprises both a rim well and a wheel disk. The wheel is manufactured by winding a fabric tube around the two halves of a mold, whereby the wheel disk can be formed by means of winding around a groove. Deposition of fibers during the winding does not, however, take place sufficiently in a positive-locking manner; hence, the fabric tube must be additionally wound around with fabric tape or filaments. A forming of the wheel disk already during the deposition of the fiber layers is not disclosed.
The subject of DE 42 23 290 B4 is a composite synthetic resin wheel, which consists of a plurality of partial cast parts and its wheel disk passes directly over into one of the wheel flanges. The partial cast parts have a corresponding threaded section on their connecting surfaces, such that they can be joined together by means of a screw connection. Each of the individual partial cast parts consists of short-fiber-reinforced plastic, as a result of which the construction of such a rim from continuous fibers without interruption of fibers according to the disclosure of this publication is not possible. Because of the structure of the composite synthetic resin wheel, mechanical weak points must be taken into account especially at the connecting points of the partial cast parts.
DE 100 06 400 A1 discloses a disk wheel consisting of fiber-reinforced plastic at least in sections as well as a process for the manufacture thereof. In this case, the disk wheel preferably consists of a metallic rim well as well as a rim well consisting at least partly of unidirectional fiber SMC (sheet molding compound). The wheel disk and rim well are connected with one another in substance or in a positive-locking manner or by means of fastening means having a different action. In the preferred case of positive locking, the wheel disk has a plurality of pin-like projections that correspond with a plurality of holes in the rim well. Such fastening means can be constructed with fiber reinforcement only with great difficulty and hence frequently have low fiber volume percentages. Hence, reduced mechanical properties of the disclosed disk wheel compared to components constructed from fiber composites in one part had to have been assumed. Such a one-part design of a disk wheel is not described in the publication.
U.S. Pat. No. 4,721,342 A discloses a fiber-reinforced plastic wheel with an essentially three-part design. In particular, the wheel disk, consisting of fiber material, of the wheel is constructed separately and is connected in substance to the inner two hollow-cylinder-like layers of fiber material. By means of connecting the two hollow-cylinder-like fiber layers and the fiber layer forming the wheel disk first in the consolidation process, an expensive fixing of the fiber layers to one another is guaranteed during the deposition of fibers. Furthermore, reduced mechanical properties at the connection points of the individual parts compared to the rest of the component must be assumed.
An essentially two-part fiber-reinforced vehicle wheel made of composite is disclosed in US 2005/0104441 A1. The vehicle wheel consists of a fiber-reinforced rim well as well as a fiber-reinforced wheel disk, which are connected with one another in substance and in a positive-locking manner wherever possible first in the consolidation process. Thus, there is also no fiber reinforcement of the rim in the disclosed wheel precisely in the especially stressed area of the transition from the wheel disk to the rim well. According to the publication, the preforms for the rim well and the wheel disk are always prepared isolated from one another; thus, a vehicle wheel with a one-part design without interruption of fibers is not disclosed in this publication.
A light metal wheel, in which the wheel disk passes over into the outer wheel flange, is disclosed in DE 10 2004 028 841 A1 and in DE 103 02997 A1. Furthermore, the wheel may have a cavity in the undercut area of the outer wheel flange, as a result of which an especially good stability should be obtained. The design of such a wheel made of fiber composite is not disclosed in the publication.